There is an increasing recognition of the usefulness of sensors to monitor the condition of property and the operation of appliances. Typically, power outlets or batteries are used to provide power for sensors. In some instances, where sunlight is available, solar power may be also utilized.
However, each of the above listed sources of power has limitations. For example, for some sensors, no direct pathway to sunlight is available. The wiring required to connect a sensor to a power outlet may be expensive to install. Batteries often discharge after a period of time and need to be replaced. This can present a difficulty when the sensor is not readily accessible. Even when the sensor is accessible, it is often difficult to detect when a battery is discharged. The necessary monitoring of the condition of the battery can be inconvenient and therefore neglected.
It is desirable, therefore, to explore other potential power sources for sensors.